Addition of Intrathecal Magnesium Sulfate to Bupivacaine for Spinal Anesthesia in Cesarean Section

Adults aged 18 to 35 years with ASA class I-II status undergoing cesarean section under spinal anesthesia were studied in Iran. The active arm received intrathecal magnesium sulfate plus bupivacaine, with perioperative sensory, motor, analgesic, hemodynamic, and safety outcomes assessed.

A single intrathecal dose of magnesium sulfate 50 mg was added to hyperbaric bupivacaine 0.5% 10 mg for spinal anesthesia during cesarean section. The regimen was given by intrathecal route once, as the active regimen being tested against bupivacaine alone.

Intrathecal magnesium sulfate did not provide a meaningful overall benefit for cesarean spinal anesthesia. It delayed sensory block onset versus control (P = 0.01) but did not improve motor block onset (P = 0.56), regression of four sensory blocks (P = 0.19), or produce a clearly significant extension of analgesia (P = 0.07). Heart rate and systolic blood pressure were similar between groups, and nausea/vomiting occurred in 3 patients in the magnesium sulfate group versus 1 in control; no neurologic deficits were observed and Apgar scores were similar. The authors concluded that adding intrathecal magnesium sulfate to bupivacaine is not desirable for cesarean section spinal anesthesia.

The evaluation was limited to a single perioperative intrathecal dose in generally healthy ASA I-II cesarean patients, so generalizability is narrow. Several key outcomes were not significantly improved, and some findings were only borderline or not fully significant, limiting confidence in clinical benefit.